Method of producing visual effects



Oct. 20, 1931. c WATSON 1,828,236

METHOD OF PRODUCING VISUAL EFFECTS Filed Aug. 27, 1929 2 Sheets-Sheet 1 .5/ r' Z? Q j .Z I E I I I H IN V EN TOR.

A r/bur C 'WO/SON A TTORNE Y.

Oct. 20, 1931. A. c. WATSON METHOD OF PRODUCING VISUAL EFFECTS Filed Aug. 27, 1929 2 Sheets-Sheet 2 INVENTOR. 4rf/7ur C Wafsofi A TTORNE Y.

Patented Oct'. 20, 1931 PATENT OFFICE ARTHUR C. WATSON, OF MABIET'I'A, OHIO METHOD OF PRODUCING VISUAL EiFE-CTS Application filed August 27, 1929. Serial No. 388,810.

This invention is a method of producing visual effects through the employment of nonfilament gas tubes.

Experimentation with illuminating tubes of the gaseous or non-filament type has convinced me that the inherent peculiarities of their operation render them susceptible of use for the production of visual effects heretofore not recognized or comprehended by 1 those familiar with their operation and these experiments have led to certain discoveries on which the method of the present invention is based and which will be hereinafter more fully explained.

It is well known that non-filament gas tubes, of which neon tubes may be referred to by way of example, possess the peculiarity that when energized by an intermittent electrical current, they intermittently glow wlth 2o considerable brilliancy and with well defined alternate periods of light and darkness corresponding to the current fluctuations or alternations by which they are energized. An important characteristic in the operation of these tubes resides in the fact that the change fromthe dark period to the illuminated period and vice versa is practically instantaneous. That is to say, when energized these tubes immediately come to a point of maximum brilliancy appropriate to the particular current fed thereto, maintaining such brilliancy during the period of illumination and then immediately becoming darkened. Another characteristic of this type of tube is that their periods of illumination and darkness may be of exceedingly short duration and also of an exceedingly high frequency.

The so-called persistence of vision, as is Well known, requires a minimum frequency of retinal stimulation to produce a continuous sensation free from flicker. This he quency is usually referred to as the critical frequency, and relates to that frequency necessary to produce continuous visual sensation.

It is also well known that for the obtaining of maximum brilliance of sensation a light stimulus of a given physical intensity must have a certain minimum duration in order 59 to overcome the inertia of the retina or optic nerve. Hence if very brief periods of stimulation are used as in the case of neon light, a certain minimum frequency of such perlods 1s necessary in order to bring the sensation to the maximum brilliance commensurate with the physical intensity of the light. Let us call this the critical frequency for brilllance, as the former was called the critical frequency for continuity of sensation. The essential fact here emphasized is that the high frequency of which neon lights are capable is very much greater than this critical frequency for brilliance.

It is a further fundamental principle in the laws of vision that at the so-called threshold level of vision necessary minimum intensity of light varies inversely with the angular area of the stimulus. That is to say, if a relatively small area of light of a given intensity can be barely seen at some particular distance, the increase of such area, to say twice its size, will require a light source of one-half intensity for substantially the same visibility. If the original intensity be maintained over the increased area, it will give the same brilliance as the smaller area at a greater distance. A similar gain through increased area is also obtainable at higher intensities than threshold values.

The method of the present invention depends primarily upon the foregoing fundamental characteristics of the organism of the eye on the one hand, and of the mode of operation of non-filament tubes on the other, and is based upon' certain discoveries whereby these two sets of characteristics may be so coordinated as to produce practical results in the various arts wherein optics con- 'stitute a primary factor.

I have discovered that when a relatively small source or sources of neon light of suflicient physical intensity to effect vision above the threshold level is or are intermittently tionary light, but may even have a considerably greater brilliance. This is the more remarkable in view of the fact that when an ordinary source of light of the continuous or approximately continuous type is similarly moved over the field of vision, the increase of area, as is well known, is obtained at the expense of brilliance. With a continuous light thus used, the loss of brilliance is inversely proportional to the gain in area.

I have further discovered that so great is the gain in brilliance obtainable by this method that it is possible thereby to produce the so-called "Bczold Briicke phenomenon (an apparent change in the hue of the stimulus)an ellect which has hitherto been reported only in connection with large actual increase in the physical intensity of the stimulus, whereas 1 have found it possible to produce these ell'ccts in the manner stated without increasing the electrical energy. In other words, there is a systematic shift of the hues in relation to wave-len th, an effect which is known as the Bezolt-Briicke phenomenon. This can be demonstrated through a simultaneous comparison of the hues evoked by stimuli of the same wave-lengths but of dill'erent intensities. The colors, on either side of the psychological red and green, shift in hue towards the psychological blue or ellow. (l oundations of Experimental sychol ogy, 192%), Clark University Press, page 197 To summarize in a word the significance ol this discovery. A neon light operating even at frequencies commonly used is, when in a stationary position, productive of only a comparalively small fraction of the visual ell'ectiveness of which it is capable when moved over the licld of vision with a suitable rate and mode of translation. This is because of the way in which the unique character of neon or similar light source may be made to take advantage of essential characteristics of the human eye and o )tic tract.

The foregoing principles and iscoveries may be utilized in various ways to carry out the method of this invention. For example, and without intending to limit the practicing of the present invention to specific details or character of movement, it may be slated that a relatively small source of neon light may be revolve rapidly about a fixed axis so that if the source of light embodies substantially a relatively small sector of the complete path of this movement, there will result an optical sensation of complete illuminalion of such path provided of course that the cycle of complete rotation is less than the visual critical frequency necessary to give continuous sensation and if the rotation of the source of light is continued through a succession of these cycles, the visual image which results may be retained so ion as this cycle of operation continues. Thus t ere will be produced by the example referred to a relatively large circular area of cptical stimulation well ada ted to form a murce of transmitted light or illuminating a mask having appropriate light penetratable portions and interposed between such source of light and an observer. By suitablyshaping and disposing the said light enetratable portions throughout the area ot the mask a wide variety of designs and patterns may be obtained and by properly controlling the illumination of particular areas in predetermined sequence, the resulting patterns, designs or indicia may be etfectually controlled to produce, for example, readily legible reading matter, words or symbols, or combinations thereof ossible in the daytime, as well as in the dark.

The method of the present invention may also be practiced to produce additional optical eflects by providing for relative rotation between the source of ii ht and the mask at different speeds. Furtiermore, the invention may also be practiced without the employment of a mask for the production of the visual eifects to which I have referred by appropriately shaping one or more relatively small sources of light and energizing them in predetermined sequence and at a predetermined rate of rapid succession, said source of light being either stationary or movable without departing from this invention.

In the preferred manner of practicing this invention the method consists in intermittently energizing a source of substantially instantaneous light in one position, then physically moving the light source a predetermined increment to a second position and energizing said source in said second position, then continuin the movement and energization of the light source in a like manner indefinitely through a predetermined cycle of continuous movement, the points of maximum intensity due to successive energizations of the light source being substantially uniformly spaced apart alon the path of movement of the light source t iroughout the cycle, and re eating said cycle a plurality of times with tie corresponding energizations of the several cycles juxtaposed in space and re-occurring with suflicient rapidity to satisfy the critical frequency of continuous visual sensation. This preferred method of operation contem lates substantially constant frequency in t. e operation of a neon light or equivalent light source coupled with constant rate of movement of said source along a predetermined path through space and is found in practice to give greatest brilliancy and otherwise best results which I have been able thus far to obtain.

The method of this invention is susceptible for use in widely varyin arts, in some of which it is desirable to pro ace the optical sensations of letters, words, symbols, patterns or combinations thereof, while in others of which it is desirable to produce relatively large areas of optical stimulation such, for flxainple, to guide the way of persons in the ar r.

In practicing the present invention in the latter environment a relatively small source of light may be employed to illuminate a relatively large area with increased visibility for the reasons hereinbefore stated. Features of the invention, other than those specified, will be apparent from the hereinafter detailed description and claims, when read in conjunction withthe accompanying drawings.

In the accompanying drawings, I have illustrateddiagrammatically different ways in which the methods of this invention may be practiced, but the showing therein made is to be understood as illustrative, only, and not as defining the limits of the invention.

Figure 1 shows diagrammatically the manner in which a relatively large area may be acted upon by movement of a relatively small source of light, so that the entire area appears to be illuminated.

Figure 2 is a similar view'showing the manner in which a like area may be similarly acted upon by, simultaneous movement of a plurality of sources of light; v

Figure 3 shows the manner in which predetermined patterns may be obtained with relative movement between the source of light as indicated in Fig. 1 and a screen or mask posi-- tioned between the source of light and the observer.

Figure 4 shows a further manner of illuminating an enlarged area'through the employment of a plurality of moving lamps energized in predetermined sequence.

Figure 5 shows a method of producing patterns of predetermined design through the rapid consecutive illumination in predetermined sequence of a plurality of stationary sources of light.

Figure 6 is a face view of one practical form of movable element embodying the several light sources shown in Figure 4.

Figure 7 is a section on the line 7-7 of Figure 6 showing one manner of making electrical connections illustrated in Figure 4.

Figure 8 is a' face view of one practical form of timer, whereby the stationary leads of the energizing circuits in Figure 5 may be electrically'connected to a rotating timer element.

Figure 9 is a section on the line 9-9 of Figure 8.

By reference first to Fig. 1, 1 designates a relatively large. area which it is desired to illuminate by means of a relatively small source of light 2. For the purpose of graphic description, the area 1 is shown as circular and the area 2 is shown as comprising a sector embodying substantially one-sixth of appropriate shape or a plurality of these.

tubes arranged in a cluster so as to operate in effect as one. The device may if desired be mounted for rotation without covering although in practice I preferably mount these tubes within a suitable casing of some material which will difi'use the glow of the tube in order that such glow may be substantially uniform throughout the entire area 2. This is, however, a matter of detail to which I do not restrict this invention.

As stated, a source of light 2 is adapted to rotate about the center 3 and I have shown in Fig. 1 six distinct positions adapted to be o'ccupied by this source of light during one complete rotation about said axis. These respective positions I have designated I to VI inclusive and at VII I have designated the.

visual effect produced by such rotation, i. e,

circuit. If it be assumed that the sour'ce of light 2 is mounted to rotate upon a suitable shaft and that said source of light is energized at a constant frequency from a suitable source of electrical supply, it will be intermittently illuminated or caused to glow as it passes through the six positions shown in Fig. 1 and having completed the cycle immediatelycommences a repetition thereof.

It is essential to the proper carrying out of this method that the time or duration of each complete cycle is less than the critical frequen'cy of the human eye. In other words, the cycle must be completed and a repetition of this cycle commenced within a period during which the e e will retain the image of the light source in the position 1. When the light source is rotated as specified, this source will be manifest to the human eye in not only each of the six positions illustrated in Fig. 1, but in innumerable intermediate positions due to progressive rotation with coincident intermittent illumination of the source of light. It is a fact that the human eye is capableof discerning or receiving and transmitting retinal impressions to the brain even though the frequency of these impressions is relatively high as compared to the critical frequency for continuous visual sensation, and in practice, it is only necessary that the frequency of. illumination of the sour'ce of light 2 be sufliciently rapid as to be enough faster than the critical frequency of the eye to produce a substantially continuous image constituting in effect an accumulation of the several images IVI and all intermediate illumination of the source of light remains substantially constant and, as stated, this freauency may be relatively low. If a higher egree of brilliancy is desired, the f ueno should be correspondingly higher ditlioug there is a point beyond which increase in frequency will not in'crease brillia-ncy. Sufiice it to say, however, that in any event the frequency is substantially constant and predetermined during the entire operation.

\Vhere the frequency of illumination remains constant and the movement of the source of light also remains constant it necessarily follows that the points of maximum illumination alon a predetermined path of movement of sai source are spaced at substantially equal distances throughout the cycle and as the cycle is repeated these points of maximum brilliance are substantially juxtaposed so that there is thereby produced a maximum visual sensation resulting in maximum apparent brightness.

By the arrangement illustrated in Fig. 1, I am thus able with a relatively small source of lightto produce a visual effect of illumination throughout a relatively large area.

The source of light in Fig. 1 is shown as embodving substantially one-sixth of the area, but in ractice,-it may embody a much smaller part 0? the area to be covered provided that each com letc cycle is carried on with sufiicient rapidity to be completed within the critical frequency of the eye. I have also found it in practice desirable for some purposes that the velocity of the moving source of light, the frequenc of illumination of the tube, and the size 0 the source of light to be so related to each other that the successive illuminations at successive positions may appear to be contiguous or to overlap in order to produce an optical impression continuous in area as well as in time.

In Fig. 2, I have illustrated substantially the same method as illustrated in Fig. 1, except that in Fig. 2, there are two distinct sources of li ht 2 and 2a rotating about a fixed center 3. y this arrangement, the cycle appreciably shorter than in Fig. 1, so that if the time or duration of the cycle is desir d to be the same as in Fig. 1, the rotary move ment may be accomplished at substantially one half the speed. If the rotary movement of the light sources in Fig. 2 is the same as in Fig. 1, two complete cycles wiil result during the time of one complete circuit in Figure 1.

In Fig. 3, I have illustrated the method as shown in Fig. 1 with the addition of a mask or stencil 4. If this stencil is stationary, there results in effect a circular glow of light back of the mask showing through the mask at all times so that the parts of the mask apthe mask by cutting out parts thereof or by saaaaa making portions of the mask translucent will ap ear in their true outline.

f, however, the mask 4 is rotated at a different speed than the light source 2, there will result change in patterns with increase or decrease in the rate of speed of the li ht source 2 to the rate of the mask 4 and t llS change of atterns will of course be the result of li it transmitted from the source 2 through t e cutouts of the mask and making different combinations of impressions upon the eye due to the difference in speed or rotation between the parts. A wide variety of patterns may be produced in this manner and very beautiful relatively fixed or movable patterns may be accomplished by this arrangement. n ractice,the relative rotation may be mechanically or frictionally effected as desired.

It will of course be understood that in carrying out the method as shown in Fig. 3, a plurality of light sources moving synchronously and intermittently illuminated at the same frequenc may be employed after the manner descri d in connection with Fig 2.

In Fig. 4, a further form of the invention is illustrated. Here a plurality of light sources designated, respectively, 5, 5a 56, etc, are mounte to rotate about a fixed axis 6. In this view, I have illustrated a wiring diagram appropriate for the carr in out of'the method therein shown. Eac o the light sources 5, 6a, etc. are included in separate and independent electrical circuits constituting a secondary circuit of an induction coil. Only the circuits for the source of illumination 5 are shown, but it will be understood that these are du licated for each of the other sources. T e secondary circuit to which I have referred is designated 7 and with it is associated the primary circuit 8 includin a suitable source of ower 9 and a contro switch by which t e circuit-s may be rendered effective or ineffective. The primary circuit 8 includes an up ropriate interrupter 10 shown as controlled by a cam or any other suitable mechanism 11 rotatable with the sources of light. The circuit breaker is preferably mounted upon an angularly adjustable element 12 which may be turned manually or by any suitable mechanism about the axis of rotation of the cam 11, so as to control the time or position at which the source of illumination 5 will be energized.

All of the various sources of light as stated are electrically connected in the same manner as the source 5 and all are controlled by circuit breakers associated and rotatable with these sources and all of the circuit breakers are adjustable to cause illumination of these sources at such times or angular positions of rotation as may be desired. With this arrangement, suitable symbols shown as letters A to F inclusive may be associated with the respective sources of light as by mounting transparent symbols in an opaque fieldorby forming cut outs in such a disk positioned in front of the light sources and rotatable therewith. By this arrangement, it is entirely practical to illuminate the symbols in predetermined sequence and in desired relative positions. These symbols may be of such large numbers as to permit of production of widely varying patterns or the spelling out of different words, or combinations of words. The patterns or words will of course depend upon the regulation of the respective circuit interrupters 12, so as to produce retinal stimulations which are repeated within the critical frequency of the eye at predetermined positions in the rotation of the light source to produce the patterns to which I have re ferred.

In Figure 4:, I have shown the arrangement described in a very diagrammatic way in order that the circuits may be traced in a convenient manner. Those skilled in the electrical art will readily appreciate many ways in which this wiring can be practicall carried out and additional ways in which di fusion of the light in the manner hereinbefore described can be performed. However, for the'purpose of illustration of one practical adaptation of this construction, attention is directed to Figures 6 and 7. In these views, a suitable holder 23 is shown as fixedly mounted on a shaft 24, the axis of which is the axis 6. A nut 25 is screwed on to the shaft to hold the holder in position. The holder formed with a series of segmentally ar ranged portions or pockets 25, six of which are shown and in these pockets are positioned the tubes 5, 5a,, 5b, 50, etc. which tubes may conveniently be neon tubes. The tubes are embedded in paraflin or other suitable difiusing substance indicated at 26. One terminal of each tube is grounded to the shaft 24 by ,means of an electrical lead 27, clamped beneath the nut 25, while the other poles of the several tubes are connected by wires 28 to col- .lector rings 29 mounted on and insulated from the shaft. Brushes 3O cooperate with the several collector rings and wires 31 lead to the secondary coils of the corresponding transformers. The wires 28, rings 29, brushes 30 and Wires 31 collectively constitute the circuits 7 illustrated diagrammatically in Figure 4. v

The foregoing structure is thoroughly practical for the purposes stated, but inasmuch as this application is directed to a method, I do not obviously confine myself to the use of this particular arrangement.

In each of the several ways of practicing the present invention as hereinbefore described, provision is made for the movement of one or more sources of light through space at a predetermined speed, with a periodic -'.uiergiza-tion of the light sources according to a predetermined constant frequency. I have throughout such area equal to that of a stationary light source.

To these ends, it is preferable that the veloclty of the light source or sources and the frequency of its energizat-ion be so related that the successive flashes overlap, say one-half the area of each flash, whereby there results an apparently continuous area of illumination, each and every part or zone of which is activated by at least two immediately successive flashes.

.VVith such a procedure, I am able to obtain with relatively low frequency, i. e. with two or a few flashes, at successive positions, a brilliancy equal to that produced by illumination at relatively high frequency in the same or stationary position.

Mere juxtaposition of successive luminous sectors or zones will give increased area, but in order to obtain a high degree of brilliancy throughout such area the overlapping to which I have referred should be practiced. Reference has been made to an overlapping of approximately one-half the area of the light source but such overlapping might well be less or greater than this amount, depending, of course, upon the frequency of illumination and the speed of the source of light.

Good .results are obtained when the light fields from the successive flashes so overlap one another as to form, in efiect, an aggregate of superimposed optical impressions. This imparts the increased brilliance over and above that which will result from the-mere successive illumination of consecutive spaces without such overlapping.

equal to a number 0 light sources 15, 15a, etc.,

and one terminal of each light source is con nected to these contacts through suitable connections indicated diagrammatically in this figure. The other terminal of each light source is connected to one lead of the secondary circuit 17 of a transformer or induction coil, while the other lead of the secondary circuit extends to a wiper 18 adapted to cooperate with the timer. The primary circuit 19 is controlled by an interrupter 20 rotatable with the timer 16 as shown. With this arrangement the timer and interrupter rotate in synchronism and bring about periodical periods of illumination of the several sources of light 15, 15a, etc. A mask -21 rotates coaxially of the center 14 and has formed thereon letters, or other suitable symbols which as the mask 21 rotates are illuminated by the sources of light 15, 15a, etc., as they are energized in succession at appropriate constant frequency and when the elements are respectively in positions to produce the desired patterns or other optical 1mpressions be it letter, word, symbol or complete pattern. Preferably the rate of rotation of this mask is slightly different from the rate of sequence of the successive illuminations, so that changing effects are secured as in the case of the situation suggested in Figure 3.

In Figure 5, I have shown the several sources of light stationary and electrical leads connecting these several sources of light to a rotary timer element 16. The wiring diagram of Figure'5 is made diagrammatic in order that the circuits may be more readily followed. Those skilled in the art will readily appreciate many ways in which this wiring might be accomplished and I do not restrict the invention to any particular way. For the. urpose of illustration, however, one practica structure for electrically connecting the several leads 17 to the movable timing element 16 is illustrated in Figures 8 and 9. Here the movable timing element 16 is mounted to rotate a shaft 32 which is coaxial with the mask 21 of Figure 5. This timer element is of insulating material and carries on its periphery spaced apart contacts 33 shown six in number to correspond to the six sources of light 15, 15a, 156, etc. A stationary wiper l8 coacts with the periphery of the element 16 to engage with the contacts 33. In the face of the element 16 is imbedded concentric collector rings 34, shown six in number and corresponding to the six contacts 33 and each collector ring is connected to one of the said contacts 33 by a wire 35. With each ring 34 cooperates a stationary brush 36 and each of these several brushes has a wire 37 connected to one of the sources of light 15, 15a, 1525, etc. The brush 18 has connected thereto a wire 17 which leads through the primary coil of the transformer as shown in Figure 5.

I am aware that this is but one of several electrical hook-ups that might be emplo ed by those skilled in the electrical art to eed current in the manner described and accordingly I do not limit the invention to this particular arran ement.

I have herein fore referred to the employment of the source or sources of light about a relatively fixed axis. I wish it understood, however, that the present invention is not restricted to circular movement in the nature of rotation, but that movement as hereinbefore described may partake of a rectilinear character or any other path which particular conditions may require, without departing from this invention.

As hereinbefore stated, the method of this invention and the discoveries to which I have referred are ada ted for a wide range of application, and do not restrict the invention to particular uses. However, the following concrete examples are given in order that the practical utility of the invention may be clearly understood.

To illustrate a second mode of application of the present invention in which increase of area, as obtained by this invention, may be utilized, consider a stationary neon tube formed in the shape of, for example, the letter M. Now supposethat this tube were straightened out, its length would be approximately four times as great as the height of the letter. Further if this straight tube were rotated about one extremity as a center, then an area of effectively luminous surface will be obtained equal to 1rR where R equals the length of the tube, namely, a length four times greater than the height of the original letter. In this way by placing in front of the luminous circuit area a mask in the form'of the original letter, a luminous letter will be obtained which will be approximately thirty times as large as the original let'ler with the same amount of current consumption. The increased visibility and the attention value of such an enlarged symbol will at once be ap arent.

other way in which the advantages of rotation or other movement of neon or simi lar light may be utilized as compared with the same tube in a stationary position is as follows. Suppose a plurality of neon lights arranged in a circuit and together rotated about a common center at a periodic rate suitable to the critical frequency for continuous sensation and suppose further that there are twent -six such hghts, each in the form of one o the letters of the alphabet. Suppose the individual lights are energizablc at any instant in the cycle of rotation, then because of the principle of persistence of vision and because different instants of energization may produce illumination at any desired position in the circular path of the moving light and because the illumination is practically instantaneous and consequently appears to the eye to be motionless, it is further practicable to combine any selected letters in any desired special pattern or sequence in the orbit of the lights by the simple pro cedure of properly timing the energizing of said selected lights. For example, the word light may be made to appear in space by flashing Z at the instant when it is in a given position, flashing i at the instant when it comes to a position at the side adjacent to Z, etc. It is a physical fact if the letters come in the regular alphabetical order, and if the direction of rotation is from lcft to ri ht (with reference to the sequence of letters in the word) then i will actually be illuminated before the letter Z, although it appears to be after it in space, because each letter ap ears to be continuously luminous as stated a ove. This priority is not observable to the eye.

A similar procedure can be used to operate a visual telegraphic code of dots and dashes or to perform many other numerous and interesting optical effects.

Another instance of usefulness of this method consists in the fact that by combining the red color of neon with the yellow color obtained from it as in the Bezold-Briicke phenomenon and also with other types of light such as the neon mercury tube and by placing before the rotating light a rotating mask which may itself be colored, so as to reflect daylight, it is possible to secure very color visual patterns. Furthermore, if the mask referred to be rotated at a slightly a different s eed from that of the light,

then the co ored patterns undergo a series of changes of form, as well as of color and the total effect may be upon such a large scale as to produce exceedingly attractive and beau tiful patterns of various colors. The effect of this is entirely unique and provides a visual phenomenon of remarkabe attention value and aesthetic potentialities. In case the area to be thus treated is so large or so located or so shaped as to make rotation or movement of a neon tube of adequate size mechanically difficult, the effects here described can be obtained by energizing in desired sequence and through predetermined cycles of operations, appropriately disposed stationary sources of light throughout the area to be treated.

The foregoing detailed description and various exemplary adaptations thereof are to be understood as illustrative of the broad principles which I have described and the invention is to be construed as fully commensurate with the appended claims.

-In the appended claims, I have referred to substantially instantaneous intermittent illuminations and a source of substantially instantaneous light. These statements refer to illuminations produced by neon light or from a source of neon light, as well as from a similar light as hereinbefore stated. By a similar light, I mean a light capable of producing substantially instantaneous intermittent flashes and functioning in the manner hereinbefore described to produce the results stated.

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent is 1. The method which consists in causing substantially instantaneous, intermittent illuminations in different positions along a periodic path in rapid succession through repetitive cycles satisfying the critical frequency for continuous visual sensation, producing visual effects of appreciable duration, and modifying the visual effects by interposing a mask between said-illuminations and the observer.

2. The method which consists in causing substantially instantaneous, intermittent illuminations in diflerent positions along a periodic path in rapid succession through repetitive cycles satisfying the critical frequency for continuous visual sensation, producing visual effects of appreciable duration, and modifying the visual effects by interposing a moving mask between the illuminations and the observer.

3. The method which consists in causing substantially instantaneous, intermittent i1- luminations in different positions along a periodic path in rapid succession through repetitive cycles satisfying the critical frequency for continuous visual sensation, producing visual effects of appreciable duration, and interposing a mask between the said illuminations and the observer and moving said mask at speed different from the speed of change of position of said illuminations to modify said visual effects.

4. The method which consists in causing substantially instantaneous, intermittent illuminations in different positions along a pcriodic path in rapid succession through repetitive cycles satisfying the critical frequency for continuous visual sensation, producing visual effects of appreciable duration,

interposing a mask between said illuminations and moving said mask in the same direction as the change of position of the illuminations, and at a different speed therefrom to modify said visual effects.

5. The method which consists in intermittently energizing a source of substantially instantaneous light of relatively small area, causing said source of light to change position through predetermined repetitive cycles, satisfying the critical frequency for continuous visual sensation, to thereby apparently increase the area of illumination, energizing the source of light a plurality of times in succession at each energizing point in each cycle to increase the brilliancy thereof, and causing said cycle tobe repeated a plurality of times for the purpose of prolonging such apparent increase in area of illumination for an appreciable period of duration.

6. The method which consists in intermittently energizing a source of substantially instantaneous light of relatively small area, causing said source of light to change position through predetermined Y repetitive cycles, satisfying the critical frequency for continuous visual sensation, to thereby apparently increase the area of illumination, causing said cycle to be repeated a plurality of times for the purpose of prolonging such apparent increase in area of illumination for an appreciable period of duration, modifying the resulting visual effects by interposing a mask between the field of apparent illumination and the observer.

'7. The method which consists in intermittently energizing a source of substantially instantaneous light of relatively small area, causing said source of light to change position through predetermined repetitive cycles, satisfying the critical frequency for continuous visual sensation, to thereby apparently increase the area of illumination, causing said cycle to be repeated a plurality of times for the purpose of prolonging such apparent increase in area of illumination for an appreci able period of duration, interposing a mask between the field of apparent illumination and the observer, and moving said mask at a speed different from the speed of change of position of the light source.

8. The method which consists in intermittently energizing a source of substantially instantaneous light of relatively small area, causing said source of light to change position through predetermined repetitive cyeles, satisfying the critical frequency for continuous visual sensation, to thereby apparently increase the area of illumination, causing said cycle to be repeated a plurality of times for the purpose of prolonging such apparent increase in area of illumination for an appreciable period of duration, interposing a mask between the field of apparent illumination and the observer, and moving said mask in the same direction and at a different speed than the movement of the light source.

9. The method of supplying an apparent source of light over a relatively large area from a relatively small actual source of light, which consists in producing at said actual source intermittent, substantially instantaneous flashes of light, causing said actual source of light to rapidly change position along a predetermined path and through predetermined repetitive cycles-satisfying the critical frequency for continuous visual sensation, causing a plurality of successive flashes to occur at each one of av plurality of predetermined points in said path during each cycle. and causing said cycle to be repeated a plurality of times to prolong the resulting visual sensation.

10. The method of supplying an apparent source of light over a relatively large area from a relatively small actual source of light, which consists in producing at said actual source intermittent, substantially instantaneous flashes of light, causing said actual source of light to rapidly change position along a predetermined path and through predetermined repetitive cycles satisfying the critical frequency for continuous visual sensation, causing said cycle to be repeated a plurality of times, and interposing a mask having light penetratable portions between the said apparent source. of light and an observer, to

cause illumination of said light penetratable portions of the mask.

11. The method of supplying an apparent source of light over a relatively large area from a relatively small actual source of light, which consists in producing at said actual source intermittent, substantially instantaneous flashes of light, causing said actual source of light to rapidly change position along a predetermined path and through predetermined repetitive cycles satisfying the critical frequency for continuous visual sensation, causing said cycle to be repeated a plurality of times, interposing a mask having light penetratable portionsbetween the said apparent source of light and an observer, to cause illumination of said lightpenetratable portions of the mask, and moving said mask at a speed different from speed of change of position of the actual source of light.

12. The method which consists in producing, over a relatively large area, substantially instantaneous, intermittent flashes of light.

from relatively small light sources positioned throughout said area, causing said flashes to emanate from the several sources in predetermined sequence through predetermined repetitive cycles, satisfying the critical frequency of continuous visual sensation, and repeating said cycle for an appreciable period to maintain the resulting visual effects for such period.

13. The method which consists in producing, over a relatively large area, substantially instantaneous, intermittent flashes of light from relatively small light sources moving in said area, causing said flashes to emanate from the several sources in predetermined sequence through predetermined repetitive cycles, satisfying the critical frequency of continuous visual sensation, and repeating said cycle for an appreciable period to maintain the resulting visual effects for such period.

14. The method which consists in producing, over a relatively large area, substantially instantaneous, intermittent flashes of light from a plurality of relatively small light sources of appropriate shape moving in said area, causing said flashes to emanate from the several sources in predetermined repetitive cycles, satisfying the critical frequency of continuous visual sensation, repeating said cycle for an appreciable period, and timing the illumination of the several light sources With respect to their relative positions and rate of movement to produce the desired arrangement of the resulting retinal simulations to thereby obtain a composite visual image.

15. The method of producing Bczold- Briicke effects which consists in moving a relatively small intermittently energized source of neon light along a predetermined path through predetermined repetitive cy segmentally dis instantaneous hght about avfixed axis, at a resulting cles, satisfying the critical for continuous visual sensation to thereb produce an increased area of retinal stim ation,-- energizing said light a plurality of times succession at each point in said c ole, causing each one of a p urality of predetermined points in each complete rotation of said source of light, and maintaining such relationship between intensity of illumination frequency of illumination, area of the sai source 0 illumination, and the velocity of rotation that the efiectiveness of the stimulating light on the eye is enhanced.

17. The method which consists'in rotatin a relatively small. intermittently energiz sed sourceof substantially rate of rotation satisfyin' the critical frequency of continuous vlsu sensation. to prouce a circular area of apparent illumination greatly in excess of the actual area of the. source of light, and can said light source to flash a plurality of times in suc? cession at each succeeding point in its travel to produce a brilliancy as-great as the brilliancy of the small source when stationary.

18. The method which consists in-successively producin substantially instantaneous flashes of "light om a number of stationary light sources disposed in predetermined relation to one another so as to be within the ran e of vision of an observer, causing said flas es to emanatefrom the several sources in predetermined sequence and iii; repet1t1ve cycles of such short duration and' rapid succession as to satisfy the critical frequency of continuous visual sensation for the purpose of producing a composite visual image of said flashes.

19. A method which consists in intermittently energizing a source of substantially instantaneous light in one position to establish a light field, then physicall moving said source of light a predetermined increment to a second position, and energizing said source in said second position to establish a second light field, said second light field at least partially overlapping the first light field, then continuing the movement and energization of. the light source in like manner indefinitely throughout a predetermined cycle of c0ntinuous movement so that every part ofsaid path of movement of the light source is actiquency of vatcd b a plurality of immediately s uccessive es of light from said source during each cle. 4

emethod which consists in producingyover a relatively large area, substantial- }y-instantaneous, intermittent flashes of light om relatively small light sources positioned throughout said area, causing said flashes to emanate from the several sources in predetermined sequence throughpredetermined repetitive cycles, satisfying the critical frecontinuous visual sensation each source of light being operated to pro uce a plurality of flashes at each operation-thereof, and repeating said cycle for an appreciable riod to maintain the resulting visual effects or such period.

21. The method which consists in producing, over a relatively large area, substantially instantaneous, intermittent flashes of light from relatively small light sources moving in said area, causing said flashes to emanate fromthe several sources in predetermined sequence through redetermined repetitive cycles, satisfying t e critical frequency of continuous visual sensation, each source of 1i ht being operated to produce a lurality o flashes at each operation thereof peating said cycle for an appreciable period to maintain the resulting visual eflects for such period.

22. The herein described method which consists in stimulating the human eye from a and re succession of points in space by stimulating the eye from each point by a plurality of substantially instantaneous intermittent flashes of light of uniform brightness emanating from said point with intervening brief periods of non-stimulation, occurring in rapid sequence and over a suflicient period to produce the desired degree of brilliancy, thereupon discontinuing the flashing of said light from said point for a relatively long period, the conclusion of which marks the end of one series of steps or stages, and repeating said series of steps or stages with sufiicient rapidity to reduce persistance of vision.

23. he methodwhich consists in intermittently energizing a source of substantially instantaneous light while it is movin throu h one zone, to produce a plurality 0% light ashes in said zone, then physically continuing, the movement of the light source a predetermined increment through a second zone, and energizing said source during its passage throng sai second zone to produce a plurality of light flashes in said second zone,

then continuin the movement and energizaw tion of the lig t source in a like manner in-P definitely through a predetermined cycle of continuous movement. a

24. The herein described method which consists in stimulating the human eye from a stantiall instantaneous intermittent flashes of neon 'ght of uniform brightness emanating from said point with intervening brief periods of nonstimulation, occurring in rapid sequence and over a sufiicient 'period to produce the desired degree of brilliancy, thereupon discontinuing the flashing of said light from said point for a relatively long period, the conclusion of which marks the end of one series of steps or stages, and repeating said series of steps or stages with suflicient rapidity to produce persistence of vision.

Signed by me at Marietta, Ohio, this 24th 6 day of August, 1929.

ARTHUR G. WATSON. 

